Pushbutton switch with coil spring contact

ABSTRACT

A switching device comprising a first electrode mounted on the plain surface of an insulation plate and a second electrode formed on said plain surface of said insulation plate at a sufficient spacing from the first electrode to be insulated from said first electrode and with a different diameter from that of said first electrode. The electric connection of both electrodes is effected by keeping one end of a coil spring connected to either of said electrodes and compressing the other end of the coil spring upon depression of an actuator, so as to connect said other end of the coil spring to the other of the electrodes.

[451 Oct. 15,1974

[ PUSHBUTTON SWITCH WITH COIL SPRING CONTACT [75] Inventors: Yukio Kashio, Tokyo; Hiroshi Ishii,

Sagamiko-machi, both of Japan [73] Assignee: Casio Computer Co., Ltd., Tokyo,

Japan [22] Filed: Sept. 6, 1972 [21] Appl No.: 286,843

[30] Foreign Application Priority Data Mar. 9, 1972 Japan 47-23607 [52] US. Cl 200/276, 200/159 R, 200/292 [51] Int. Cl. ..H01h l/06, H0111 13/52 [58] Field of Search 200/159 R, 159 A, 166 BA, 200/166 PC, 166 SH, 276, 292

3,679,853 7/1972 Holzer 200/166 PC X FOREIGN PATENTS OR APPLICATIONS 560,809 6/1929 Germany ZOO/166 BA 872,778 6/1942 France 200/166 BA Primary ExaminerRobert K. Schaefer Assistant ExaminerWilliam J. Smith Attorney, Agent, or Firm-Flynn & Frishauf [57] ABSTRACT A switching device comprising a first electrode mounted on the plain surface of an insulation plate and a second electrode formed on said plain surface of said insulation plate at a sufficient spacing from the first electrode to be insulated from said first electrode and with a different diameter from that of said first electrode. The electric connection of both electrodes is effected by keeping one end of a coil spring connected to either of said electrodes and compressing the other end of the coil spring upon depression of an actuator, so as to connect said other end of the coil spring to the other of the electrodes.

18 Claims, 3 Drawing Figures PUSIIBUTTON SWITCH WITI-I COIL SPRING CONTACT This invention relates toa switching device which effects the electric connection and disengagement of two electrodes by the compression and elastic repulsion of a coil spring whose ends have different diameters.

Calculators or push button type telephones are provided with a large number of switching devices for storing digits or carrying out various types of operations These switching devices are selectively operated to form electric circuits, thereby generating required electric signals. Heretofore, said switching devices have mostly consisted of a plate spring fitted with a movable contact strip. Such plate spring typing switching device raises problems with durability in long use. Further, excessively forceful depression of the plate spring results in the vibration of the movable contact strip and in consequence chattering in the contact section. Such chattering gives rise to the same result as if the same digit were repeatedly stored by a single depression of a key, failing to effect a proper switching operation. Moreover, said chattering possibly leads to the generation of noise signals and in consequence erroneous switching operations.

It is accordingly the object of this invention to provide a durable, reliable switching device free from the above-mentioned drawbacks accompanying the prior art switching devices.

SUMMARY OF THE INVENTION The switching device of the present invention comprises a coil spring, both ends of which are of different diameters, said coil spring having one of the ends kept in contactwith either of two electrodes and the other end connected to the other of said two electrodes when said other end is compressed upon depression of an actuator for electrical connection of said electrodes, thereby attaining a switching operation with a gentle stroke applied on the coil spring without giving rise to erroneous operations of the switching device, for example, due to chattering.

The present invention can be more fully understood from the following detailed description when taken in connection with the accompanying drawing, in which:

FIG. I is a perspective view of the dismembered parts of a switching device according to an embodiment of this invention;

FIG. 2 is a sectional view of the main part of a switching device according to said embodiment; and

FIG. 3 is a perspective view of the dismembered parts of a switching device according to another embodiment of the invention.

As illustrated in FIG. 1, there are formed on an insulation substrate 11 a group of first disk-shaped electrodes l2, l3 and 14 at a substantially equal spacing, for example, by thermally depositing a metal layer. Each of the first electrodes l2, l3 and 14 is perforated, as shown in FIG. 2, with a through hole 15 penetrating the insulation substrate 11 and connected to a leadout terminal 16 provided on the underside of the insulation substrate 11. On said substrate 11 are further equidistantly mounted a group of second electrodes I7, 18 and 19 in concentric relationship with the first group of electrodes l2, l3 and 14 respectively. According to the embodiment of FIG. 1, the group of said second electrodes l7, l8 and 19 are collectively connected to a common leadout terminal 20 disposed in the surface of the insulation substrate 11. However, the second electrodes 17, 18 and 19 may be connected to separately provide leadout terminals respectively. On the individual groups 12-17, 13-18 and 14-19 of said first and second electrodes are mounted conical coil springs 21, 22 and 23 respectively. The larger diameter section or base of the conical coil spring is kept in contact with the larger diameter or second electrode. When compressed from above, the smaller diameter section or top of the conical coil spring touches the smaller diameter or first electrode, so as to effect the electric connection of both first and second electrodes. The coil springs 21, 22 and 23 are compressed when the corresponding actuators 24, 25 and 26 are depressed. These actuators 24, 25 and 26 are supported by a frame 27 so as to move vertically, with their heads projecting upward from said frame 27. With a switching device of the above-mentioned construction, depression of the actuator causes the top of the coil spring to be slowly brought down for contact with the first electrode, resulting in substantially no chattering and in consequence preventing any erroneous operation of the switching device. Further, depression of the actuator can be effected with a gentle stroke, attaining a reliable switching operation.

If the first electrode of the foregoing embodiment is formed of elastic material, for example, conductive rubber, then chattering will be more effectively prevented.

According to said embodiment, the conical coil spring had its larger diameter section or base kept abutting against the second electrode and also had its smaller diameter section or top detachably engage the first electrode according to the manner in which the actuator is operated. Conversely, it is possible to keep the smaller diameter section or top of the conical coil spring pressed against the first electrode and cause the larger diameter section or base of said spring detachably to engage the second electrode.

There will now be described by reference to FIG. 3 a switching device according to another embodiment of this invention. On an insulation substrate 11 are equidistantly formed electrodes l2, l3 and 14, for example, by thermal deposition of a metal layer. According to this embodiment, there is used an elastic plate electrode 28 to provide a group of second electrodes. Equidistant sections of said plate electrode 28 are cut in helical form, for example, by etching. The helical portions thus cut are drawn out to constitute conical springs 41, 42 and 43 as shown in FIG. 3. The other members are constructed and operated in the same manner as in FIG. 1, and description thereof is omitted. The feature vof FIG. 3, is, however, that since said coil springs 41,

What we claim is: 3 'I'TA switching device comprising:

an insulation substrate having a nearly plain first surface;

a first nearly plain electrode mounted on said first surface of said insulation substrate;

a second nearly plain electrode mounted on said first surface of said insulation substrate and around said first electrode at a specified distance from the first electrode;

a first leadout means coupled to and leading out the first electrode from the surface of the insulation substrate opposite said first surface, said first leadout means extending through said insulation substrate;

a second leadout means on said first surface of said insulation substrate coupled to and leading out the second electrode from said first surface of said insulation substrate;

a coil spring made of a conductive material having one end always in contact with one of the first and the second electrodes and the other end spaced from the remaining electrode when not depressed and in contact with the remaining electrode when depressed so as to electrically connect both;electrodes when said coil spring is depressed;

an actuator coupled to said coil spring to depress said other end of said coil spring so as to cause said coil spring to electrically connect the first and the second electrodes when depressed and to be spaced a frame carrying said actuator and defining a linear stroke of said actuator to selectively depress said coil spring.

2. A switching device according to claim 1 comprising a plurality of said first electrodes, second electrodes, leadout means, coil springs and actuators associated with said insulation substrate.

3. A switching device according to claim 2 wherein said second leadout means are coupled to a common terminal.

4. A switching device according to claim 2 wherein said first leadout means are each coupled to terminals.

5. A switching device according to claim 2 wherein said one end of saidcoil springs are kept abutting against a respective second electrode.

6. A switching device according to claim 1 wherein said first electrode is generally disc-shaped.

7. A switching device according to claim 6 wherein said second electrode is generally ring-shaped and is concentric with said disc-shaped first electrode.

8. A switching device according to claim 2 wherein said actuator is slidably mounted in said frame member.

9. A switching device according to claim 1 wherein said first and second electrodes are substantially coplanar.

10. A switching device according to claim 1 wherein said second electrodes are substantially concentric with respective ones of said first electrodes.

11. A switching device comprising:

an insulation substrate have a substantially plain surface;

a plurality of first electrodes formed on said plain surface of said insulation substrate;

a plurality of second electrodes extending from and integral with a conductive plate closely superposed on said insulation substrate and formed by cutting in a helical form those portions of said conductive plate which face said first electrodes and drawing out the helical sections thus cut into conical coil springs, said coil springs having their top ends electrically connected to respective first electrodes when said coil springs are compressed from above;

a common frame member; and

a plurality of actuators arranged in said frame member and associated with respective coil springs for compressing, when depressed, the top end of said respective coil springs, thereby electrically connecting respective first and second electrodes and, when released, disengaging said spring from said respective first electrode.

12. A switching device according to claim 11 wherein said first electrodes are generally disc-shaped.

1 3. A switching device according to claim 11 wherein said first electrodes are each coupled to respective terminals.

14. A switching device according to claim 11 wherein said actuators are slidably mounted in said frame member.

15. A switching device according to claim 11 including means extending through the thickness of said insulation substrate and electrically coupling at least one of said first electrodes to a terminal.

16. A switching device according to claim 15 wherein said terminal is on the side of said substrate opposite to said plain surface of said insulation substrate on which said electrodes are formed.

17. A switching device according to claim 15 wherein said coupling means extends through a hole in said substrate, said hole being substantially concentric with respective first electrodes.

18. A switching device according to claim 11 wherein said first electrodes are plain electrodes. 

1. A switching device comprising: an insulation substrate having a nearly plain first surface; a first nearly plain electrode mounted on said first surface of said insulation substrate; a second nearly plain electrode mounted on said first surface of said insulation substrate and around said first electrode at a specified distance from the first electrode; a first leadout means coupled to and leading out the first electrode from the surface of the insulation substrate opposite said first surface, said first leadout means extending through said insulation substrate; a second leadout means on said first surface of said insulation substrate coupled to and leading out the second electrode from said first surface of said insulation substrate; a coil spring made of a conductive material having one end always in contact with one of the first and the second electrodes and the other end spaced from the remaining electrode when not depressed and in contact with the remaining electrode when depressed so as to electrically connected both electrodes when said coil spring is depressed; an actuator coupled to said coil spring to depress said other end of said coil spring so as to cause said coil spring to electrically connect the first and the second electrodes when depressed and to be spaced from said one of the electrodes when released; and a frame carrying said actuator and defining a linear stroke of said actuator to selectively depress said coil spring.
 2. A switching device according to claim 1 comprising a plurality of said first electrodes, second electrodes, leadout means, coil springs and actuators associated with said insulation substrate.
 3. A switching device according to claim 2 wherein said second leadout means are coupled to a common terminal.
 4. A switching device according to claim 2 wherein said first leadout means are each coupled to terminals.
 5. A switching device according to claim 2 wherein said one end of said coil springs are kept abutting against a respective second electrode.
 6. A switching device according to claim 1 wherein said first electrode is generally disc-shaped.
 7. A switching device according to claim 6 wherein said second electrode is generally ring-shaped and is concentric with said disc-shaped first electrode.
 8. A switching device according to claim 2 wherein said actuator is slidably mounted in said frame member.
 9. A switching device according to claim 1 wherein said first and second electrodes are substantially coplanar.
 10. A switching device according to claim 1 wherein said second electrodes are substantially concentric with respective ones of said first electrodes.
 11. A switching device comprising: an insulation substrate have a substantially plain surface; a plurality of first electrodes formed on said plain surface of said insulation substrate; a plurality of second electrodes extending from and integral with a conductive plate closely superposed on said insulation substrate and formed by cutting in a helical form those portions of said conductive plate which face said first electrodes and drawing out the helical sections thus cut into conical coil springs, said coil springs having their top ends electrically connected to respective first electrodes when said coil springs are compressed from above; a common frame member; and a plurality of actuators arranged in said frame member and associated with respective coil springs for compressing, when depressed, the top end of said respective coil springs, thereby electrically connecting respective first and second electrodes and, when released, disengaging said spring from said respective first electrode.
 12. A switching device according to claim 11 wherein said first electrodes are generally disc-shaped.
 13. A switching device according to claim 11 wherein said first electrodes are each coupled to respective terminals.
 14. A switching device according to claim 11 wherein said Actuators are slidably mounted in said frame member.
 15. A switching device according to claim 11 including means extending through the thickness of said insulation substrate and electrically coupling at least one of said first electrodes to a terminal.
 16. A switching device according to claim 15 wherein said terminal is on the side of said substrate opposite to said plain surface of said insulation substrate on which said electrodes are formed.
 17. A switching device according to claim 15 wherein said coupling means extends through a hole in said substrate, said hole being substantially concentric with respective first electrodes.
 18. A switching device according to claim 11 wherein said first electrodes are plain electrodes. 